Vacuum sewer system

ABSTRACT

The invention relates to a method for transporting waste material in a vacuum sewer system, which includes a source of waste ( 1 ), a sewer pipe ( 2, 21, 22 ), a first discharge valve ( 3 ) between the source of waste ( 1 ) and the sewer pipe ( 1, 21 ), a second discharge valve ( 4 ) in the sewer pipe ( 2 ), a waste receiving space and means ( 100 ) for generating vacuum into the sewer pipe. Waste is transported in the form of waste slugs, whereby during a first phase, the waste slug is conveyed from the waste source ( 1 ) through the first discharge valve ( 3 ) into the sewer pipe ( 2, 21, 22 ) by way of vacuum, and in a second phase, waste is conveyed further in the sewer pipe ( 2, 21,22 ), in the direction of the receiving space. For automatically adjusting the flush cycle according to the waste slug, in the first phase, the pressure flow after the waste slug, higher than said vacuum, is introduced from the location ( 9 ) after the first discharge valve ( 3 ) to the second discharge valve ( 4 ) for closing the same so that the flow through the first discharge valve is stopped, and in the second phase, a vacuum connection to the second discharge valve ( 4 ) is activated for opening the same.

[0001] The invention relates to a method for transporting waste materialin a vacuum sewer system according to the preamble of claim 1. Theinvention also relates to a vacuum sewer system.

[0002] This kind of vacuum sewer systems are previously known. However,the noise level related to the flush sequences of the known systems ishigh. Further, assuring that the source of waste, for example the toiletbowl of the toilet unit, is emptied of all waste requires adjusting ofthe flush sequence so that it is long enough for letting even largerquantities of waste to be discharged down the drain during the flushsequence, which also has a decisive influence on the noise level.

[0003] An object of the invention is to provide a method by which theabove-mentioned disadvantages are avoided and which makes it possible totransport the waste efficiently with simple means. The object isattained by a method according to the invention the main features ofwhich are given in claim 1.

[0004] The basic idea of the invention is to determine the length of theflush sequence automatically according to the amount of waste, i.e. thesize of waste batch or discrete waste slug to be transported, in whichcase the amount of air per flush sequence is constant. When the seconddischarge valve is closed after the waste batch has been transportedthrough the first discharge valve, the flow, and thereby also thepassage of air, via the first discharge valve is terminated.

[0005] The flow through the first discharge valve is accelerating innature in which case the flow rate increases from the starting moment ofthe flow, in other words from the beginning of the waste batch, untilthe flow stops. The so-called after-air subsequent to the waste batchaccelerates the flow rate even more in proportion when the flowresistance is smaller. The flow resistance is in direct proportion tothe noise level.

[0006] In the present invention, the amount of after-air passing throughthe first discharge valve is optimized, particularly minimized, in whichcase the flow rates decrease, which lowers the noise levelsignificantly. Further, the function of the flush or discharge sequenceis pneumatically controlled with a control means by using vacuumprevailing in the vacuum sewer system.

[0007] The closing of the second discharge valve is preferablycontrolled in a way that with the control means, the connection of thevacuum to an auxiliary valve for opening thereof it is activated, sothat a flow connection is formed between the waste batch passinglocation after the first discharge valve and the second discharge valve,in which case the auxiliary valve is closed after a predetermined timesince the waste batch flow through the first discharge valve hasstopped.

[0008] The control means advantageously activates also the connection ofthe vacuum to the first discharge valve for opening of the same, inwhich case the closing takes place after a predetermined time since thewaste batch flow through the first discharge valve has stopped.

[0009] Further, the control means advantageously activates theconnection of the vacuum to the rinse water valve for opening of thesame, in which case the rinse water valve is closed after apredetermined time subsequent to the closing of the first dischargevalve.

[0010] For increasing the discharge efficiency of the system, there isalso an aeration valve preferably connected to the sewer pipe, in whichcase the control means can advantageously activate the connection of thevacuum to the said aeration valve for opening the same after apredetermined time subsequent to the opening of the first dischargevalve for passing transport air into the sewer pipe, in which case theaeration valve is closed after a predetermined time subsequent to theopening of the second discharge valve.

[0011] The predetermined times related to the above-mentioned valves areadvantageously controlled with the help of flow restrictors inconnection with the control means and said valves. The flow restrictorsare advantageously nozzles, whereby by changing their dimensions, thedesired time effect can be obtained. Naturally, as an alternative, anadjustable valve arrangement can be used.

[0012] The present invention further relates to a vacuum sewer system,the main features of which are given in claim 11. Preferred embodimentsof the vacuum sewer system are given in claims 12 to 18.

[0013] In the following, the invention will be described more in detail,by way of example only, with reference to the enclosed schematicdrawing.

[0014] The drawing represents a section of the vacuum sewer system whichincludes a source of waste, in this example a toilet unit 1, a sewerpipe 2, which comprises a first section of the sewer pipe 21 and asecond section of the sewer pipe 22, a first discharge valve 3 betweenthe toilet unit 1 and the first section of the sewer pipe 21 as well asa second discharge valve 4 in the sewer pipe 2, i.e. between the firstsection of the sewer pipe 21 and the second section of the sewer pipe22. The second section of the sewer pipe 22 leads to a waste receivingspace, not shown in the drawing. The vacuum sewer system furtherincludes a means for generating vacuum in the sewer pipe 2, which meanshas been represented only as a reference by an arrow 100.

[0015] A control system is connected to the toilet unit 1 whichautomatically controls the length of the toilet unit 1 flush cycleaccording to the amount of waste transported from the toilet bowl 11 tothe sewer pipe 2.

[0016] The control system includes a control means 5, from which thereis a flow connection, by means of tube means, to the second section ofthe sewer pipe 22, which is under a constant vacuum maintained in thevacuum sewer system. The flow connection is arranged at a location 6situated after the second discharge valve 4, i.e. on the waste receivingside of the second discharge valve 4. Correspondingly, there is a flowconnection from the control means 5 to an aeration valve 7 and anauxiliary valve 8 connected to the first section of the sewer pipe 21.Further, a flow connection by means of a tube means is arranged from thecontrol means 5 to the first discharge valve 3 and to a rinse watervalve 10 of the toilet unit. A pneumatic activator means 12 is connectedto the control means 5 by means of the tube means forming the flowconnection.

[0017] A first tube means 51 between the control means 5 and the secondsection of the sewer pipe 22 is joined to a second tube means 52 betweenthe auxiliary valve 8 and the second discharge valve 4 by means of afirst tube portion means 71, in which a first flow restrictor 31 isarranged. The first tube means 51 has a first non-return valve 41 and asecond non-return valve 42 arranged on opposite sides of the connectionlocation of the first tube portion means 71.

[0018] A second tube portion means 72 leading to valve 7, which branchesoff a third tube means 53 leading from the control means 5 to theauxiliary valve 8 is provided with a second flow restrictor 32.

[0019] In the rinse water valve 10 there is arranged a third flowrestrictor 33 and in the control means 5 there is arranged a fourth flowrestrictor 34.

[0020] The above-mentioned flow restrictors 31, 32, 33 and 34 arepreferably nozzles in which case, by changing the dimensions of thenozzles, the desired effect can be provided. Alternatively, theadjustable valve arrangement can be used.

[0021] The vacuum sewer system according to the example has thefollowing operation principle.

[0022] When the toilet unit 1 is in state of rest the first dischargevalve 3 is closed. The aeration valve 7 and the auxiliary valve 8connected to the first section 21 of the sewer pipe 2 are also closed.The auxiliary valve 8 is a diaphragm valve, which in a closed-positionshuts off the connection between the second tube means 52 and an eighttube means 58 and which correspondingly opens said connection when it isin an open-position. The second discharge valve 4 is open because it isconnected to the sewer pipe 2 (more exactly to the second section 22 ofthe sewer pipe 2, which is under the vacuum maintained in the vacuumsystem) through a connection formed by the first tube portion means 71and the second tube means 52.

[0023] When the toilet unit 1 has been used and there is wasteaccumulated in the toilet bowl 11, the intention is to flush the wastedown to the sewer pipe 2 and the flush sequence is activated byaffecting the pneumatic activator means 12. This can preferably be forexample a flush button in connection with a bellows system, which bypressing the flush button provides an air pulse through a fourth tubemeans 54 to the direction of the control means 5.

[0024] The air pulse created by the pneumatic activator means 12 isarranged to affect the control means 5 in such a way that the vacuum isconnected from the sewer pipe 2 via the first tube means 51 to the firstdischarge valve 3 through a fifth tube means 55 connected thereto, inwhich case the first discharge valve opens up. Correspondingly, thevacuum is connected to the auxiliary valve 8 through the third tubemeans 53, to the rinse water valve 10 through a sixth tube means 56 andto the aeration valve 7 through the third tube means 53 and the secondtube portion means 72, in which case the said three valves open up aswell. The aeration valve 7 is arranged to open with a predetermineddelay under the influence of the second flow restrictor 32.

[0025] When the first discharge valve 3 has opened, the ambient airpressure prevailing in the toilet bowl 11 pushes the waste in the bowland rinse water into the sewer pipe 2 maintained under vacuum throughthe discharge valve 3. In such a vacuum sewer system the waste displacesor moves along intermittently and in the form of so-called waste batchesor discrete waste slugs, which fill up the diameter of the sewer pipecompletely. This also means that the waste slugs are followed by apressure front higher than said underpressure.

[0026] To a predetermined location 9 of the sewer pipe 2, in other wordsto the first section of the sewer pipe, preferably almost immediatelyafter the first discharge valve 3, a flow connection is arranged to theauxiliary valve 8 by means of the eight tube means 58. When the wasteslug passes this location 9, the pressure front in question causes asudden increase in pressure which moves under the influence of the saidvacuum control of the eight tube means 58 through the auxiliary valve 8in its open-position and further via the second tube means 52 to thesecond discharge valve 4 and closes it. Therefore, the flow through thefirst discharge valve 3 stops.

[0027] When the predetermined control period of the control means 5,i.e. in practice the prolonged vacuum effect provided by the fourth flowrestrictor 34, ends, the ambient air pressure is connected to the tubemeans 53, 72, 55 and 56 and it has an effect on the first dischargevalve 3, the auxiliary valve 8, the aeration valve 7 and the rinse watervalve 10, in which case the first discharge valve 3 and the auxiliaryvalve 8 close up almost immediately. The aeration valve 7 and the rinsewater valve 10 on the other hand stay open for a while because of thesecond flow restrictor 32 and the third flow restrictor 33 arrangedtherewith. By extending the opening time of the rinse water valve 10there is a water mirror provided in the toilet bowl 11 for the nextflush cycle. There is a flow connection from the rinse water valve 10 tothe toilet bowl 11 of the toilet unit 1 by means of a seventh tube means57.

[0028] Because the auxiliary valve 8 has closed up, in other words it isin its closed-position, there is air discharging (to the direction ofthe vacuum affecting the second section of the sewer pipe 22) throughthe first flow restrictor 31 (via the connection created by the secondtube means 52, the first tube portion means 71 and the first tube means51), in which case the second discharge valve 4 opens up again under thevacuum directed thereto. However, the aeration valve 7 is still open(under the influence of the second flow restrictor 32), in which casethere is transport air further helping the transportation of the wasteslug flowing into the first section of the sewer pipe 21, whereby thewaste is forced into the second section of the sewer pipe 22 and furtherinto the waste receiving space. After a time predetermined by the secondflow restrictor 32, the aeration valve 7 closes up after which the flushor discharge cycöe has been completed and the section of the vacuumsewer system in question has returned to the above-mentioned state ofrest for a new flush or discharge period.

[0029] According to what has been represented above, the first, second,third and fourth flow restrictors 31, 32, 33 and 34 are preferablynozzles so that with the dimensions of the nozzles, the control of thevacuum sewer system can be affected as desired.

[0030] The opening time of the discharge valve 3 is adjusted with thefourth nozzle 34 of the control means 5. This control also affects theopening time of the rinse water valve 10, the auxiliary valve 8 and theaeration valve 7. A smaller nozzle extends the vacuum duration ofaction, in other words the opening time of said valves.

[0031] The feeding time and amount of the auxiliary transport air iscontrolled with the second nozzle 32, in which case a smaller nozzleadds to the feeding quantity of the transport air by keeping theaeration valve 7 open for a longer time.

[0032] The first nozzle 31 on the other hand has the following effect onthe operation of the second discharge valve 4. A smaller nozzle speedsup the closing up of the valve and therefore it is possible to influencethe amount of air driven with the waste slug through the toilet bowl 11of the toilet unit 1. In known vacuum sewer systems in which the flushcycle remains constant, the amount of air conveyed to the sewer pipe 2varies according to the quantity of the waste slug. In the systemaccording to the present invention said air amount per flush cycle isalways constant. A further advantage of this arrangement, in addition tothe above-mentioned benefits, is that the capacity of the vacuum sewersystem is more easily dimensioned, which also facilitates the control ofthe system.

[0033] The level of the water mirror is adjusted in the toilet bowl 11by means of the third nozzle 33 of the rinse water valve 10. The totalwater amount is determined by interaction of the third 33 and the fourthnozzle 34 in which case smaller nozzle dimensions increase the amount ofthe fed rinsing water by prolonging the opening time of the valve.

[0034] The above description and the drawing attached thereto are onlyintended to clarify the basic idea of the invention. The method andsystem according to the invention may vary within the ensuing claims.

1-18. (canceled)
 19. A method for transporting waste material in avacuum sewer system including a source of waste, a first discharge valvebetween the source of waste and the sewer pipe, a second discharge valvein the sewer pipe, a waste receiving space, and means for generatingvacuum in the sewer pipe, wherein the waste material is transporting inthe form of slugs, the method comprising: a first phase in which thewaste slug is transported from the source of waste through the firstdischarge valve into the sewer pipe by way of vacuum; and a second phasein which the waste slug is further transported along the sewer pipetoward the receiving space; wherein during the first phase, a pressureafter the waste slug higher than the vacuum is communicated from apredetermined location downstream of the first discharge valve to thesecond discharge valve for closing the second discharge valve, therebystopping flow through the first discharge valve; and wherein during thesecond phase, a vacuum connection to the second discharge valve isactivated for opening the second discharge valve, thereby to advance thewaste slug further along the sewer pipe by vacuum.
 20. A methodaccording to claim 19, in which a vacuum connection to an auxiliaryvalve is activated by a control means for opening the auxiliary valve sothat a flow connection is formed between the predetermined locationdownstream of the first discharge valve and the second discharge valve.21. A method according to claim 20, in which the auxiliary valve isclosed after a predetermined time after waste slug flow through thefirst discharge valve has stopped.
 22. A method according to claim 21,in which the predetermined time for closing the auxiliary valve iscontrolled by a flow restrictor.
 23. A method according to claim 19, inwhich a vacuum connection to the first discharge valve is activated by acontrol means.
 24. A method according to claim 23, in which the firstdischarge valve is closed after a predetermined time after waste slugflow through the first discharge valve has stopped.
 25. A methodaccording to claim 24, in which the predetermined time for closing thefirst discharge valve is controlled by a flow restrictor.
 26. A methodaccording to claim 19, in which a vacuum connection to a rinse watervalve is activated by a control means to supply rinse water to thesource of waste.
 27. A method according to claim 26, in which the rinsewater valve closes after a predetermined time after the first dischargevalve closes.
 28. A method according to claim 27, in which thepredetermined time for closing the rinse water valve is controlled by aflow restrictor.
 29. A method according to claim 19, in which a vacuumconnection to an aeration valve in fluid communication with the sewerpipe is activated to open the aeration valve after a predetermined timeafter the first discharge valve opens, thereby to supply transport airinto the sewer pipe.
 30. A method according to claim 29, in which theaeration valve is closed after a predetermined time after the seconddischarge valve is opened.
 31. A method according to claim 30, in whichthe predetermined time for closing the second discharge valve iscontrolled by a flow restrictor.
 32. A vacuum sewer system comprising: asource of waste; a sewer pipe; a first discharge valve disposed betweenthe source of waste and the sewer pipe; a second discharge valvedisposed in the sewer pipe; a waste receiving space in fluidcommunication with the sewer pipe; a vacuum generator in fluidcommunication with the sewer pipe; and a flow connection communicatingbetween a first section of the sewer pipe at a predetermined locationdownstream of the first discharge valve and the second discharge valve.33. A vacuum sewer system according to claim 32, in which the flowconnection includes an eighth tube means between said predeterminedlocation of the sewer pipe and an auxiliary valve and a second tubemeans between the auxiliary valve and the second discharge valve,wherein the system further includes a control means, a third tube meansbetween the auxiliary valve and the control means, and a fourth tubemeans between the control means and a second section of the sewer pipedownstream of the second discharge valve.
 34. A vacuum sewer systemaccording to claim 33, further comprising a fifth tube means between thefirst discharge valve and the control means.
 35. A vacuum sewer systemaccording to claim 34, further comprising a rinse water valve in fluidcommunication with the control means through a sixth tube means, whereinthe rinse water valve is further in fluid communication with the sourceof waste through a seventh tube means.
 36. A vacuum sewer systemaccording to claim 35, further comprising an aeration valve in fluidcommunication with the control means through a third tube means and asecond tube portion means, and the aeration valve is in fluidcommunication with the first section of the sewer pipe.
 37. A vacuumsewer system according to claim 36, in which the first tube means andsecond tube means are connected to each other by a first tube portionmeans having a first flow restrictor, a second flow restrictor isattached to the aeration valve, a third flow restrictor is attached tothe rinse water valve, and a fourth flow restrictor is attached to thecontrol means.
 38. A vacuum sewer system according to claim 37, in whicheach of the flow restrictors comprises a nozzle.
 39. A vacuum sewersystem according to claim 37, in which each of the flow restrictorscomprises an adjustable valve.
 40. A vacuum sewer system according toclaim 33, further comprising a pneumatic activator means connected tothe control means through a fourth tube means.